In a mechanical examination, a human foot is a highly complicated construction. On one hand, the foot must be resilient in order that it could adapt itself to the variations in the environment and in the ground so that, at the same time, it provides the body with adequate support and balance. On the other hand, the foot should be sufficiently rigid to provide an adequate friction in relation to the ground surface, so that the horizontal forces of acceleration and deceleration that arise from the movements of the body can be transferred through the foot.
A number of studies have been performed concerning the foot, and in these studies it has been noticed that only about 40% of the population have so-called "normal" feet, whereas the rest have various faults of posture in their feet.
Faulty postures of feet cause a disturbance in the state of loading of the body and a state of extra strain, which is experienced by the person as disagreeable and which may quite frequently result in pains in the foot, ankle, knee, or in the lumbar region of the back.
Faulty postures of feet are commonly corrected by means of various orthopaedic insoles and orthopaedic shoes, but the choice of suitable orthopaedic insoles and shoes has been problematic in prior art.
In order that it should be possible to choose insoles and shoes of the right type, it must be possible to measure and to determine any faulty postures of the feet as well and reliably as possible. In this respect, with regard to the prior art, reference is made in particular to U.S. Pat. Nos. 4,062,355, 3,358,373, and 2,175,116, all of which concern various devices for the determination of the postures and loads of feet and, based thereon, for the choice of a shoe and/or of an insole of the right type.
The most remarkable drawback of the solutions set forth in the above patents is that their operation is highly complicated and requires high professional skill from the operator. This is why the techniques in accordance with these solutions have not obtained common and everyday use.
Compared with the prior art described in the above patent, a considerable improvement was provided by the method described in the applicant's earlier U.S. Pat. No. 1,278,677 and in the corresponding U.S. Pat. No. 4,917,105, in which method the orthopaedic operation of the foot is determined and, on its basis, a suitable correcting orthopaedic insole and/or shoe is chosen. Said method has been applied in practice, and in these practical applications it has been noticed that, when used correctly, said method provides an excellent and reliable result, whereby a shoe and/or an orthopaedic insole can be chosen for each foot. However, it has been a drawback of the method that the method is time-consuming and requires a relatively good training and quite extensive practical experience from the operator.
Owing to these facts, a need has arisen to develop a rapid and automatic method which is better suitable for auxiliary means in the selling of shoes and insoles in a retail store. Thus, the present invention is expressly intended as an improvement over the method of prior date employed by the applicant.